DOCUMENT RESUME ED 045 443 SF 010 1441 MJTHOR Pratt, Harry D.; And Others TITLF workbook on the Identification of Mosquito Larvae. INSTITUTION Public Health Service, Atlanta, (a. Consumer. Protection and Envircnmental Health Service. PUP DATE 69 HOT7 91n. ?DRS ?RIC! En?s Price MF-$0.r0 PC-S4.1s DESCRIPTORS Autoinstructional *Biology, *Fntomology, *Health Occupations Education, *Instructional Materials, Programed Materials, Public Health, *Taxonomy APSTRACT This self-instructional booklet is designed to enable public health workers identify larvae of some important North American moscuito species. The morphological features of larvae of the various genera and species are illustrated in a programed booklet, which also contains illustrated taxonomic keys to the larvae of 11 North American genera and to 41 of the important species. P glossary and a short bibliography are included. (At:) U S DRAINED! Of Es Eiltis ID0CATIOD I Vi EERIE _ OfIKE Of toufegOD DIPS DOCumED1 nAS DEEM frRIODKED IA AIM AS *REIM 11014 TR 111505 01011m/A 1101 ROD NG IIPOIN1S OF rElff 01010001S MIR D0105 IDECESSIMEI ISPIISEDI Offitsil Of fItt Of IDLIODOD 1051T101 0110iKT r reN WORKBOOK ON THE IDENTIFICATION OF MOSQUITO LARVAE LLJ HARRY D. PRATT CHESTERJ. STOJANOVICH ARTHUR S. KIDWELL 1969 U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service CONSUMER PROTECTION AND ENVIRONMENTAL HEALTH SERVICE Environmental Control Administration Bureau of Community Environmental Management Atlanta, Oa., 30326 CONTENTS Page Introduction 1 Part I -What is an anopheline or a culicine larva? 2 Part II -Morphology of mosquito larvae 16 Part III -Generic characters of North American mosquito larvae 35 Part 1V -Quiz 50 Part V -Illustrated key to some important species of North American mosquito larvae 56 Part VI -Glossary 74 Selected References 77 Answer sheet 78 INTRODUCTION One of the most important aspects of pest mosquito and mosquito-borne disease control programs is the accurate identification of mosquito larvae. Surveys are necessary to determine important species and to locate and delimit their breeding places before planning any draining or filling opera- tions, other types of source reduction or the proper application of insecticides with hand, power, or aerial equipment. The accurate determina- tion of mosquito larvae is obviously of utmost importance in making such an assessment. This manual is based on the experience of many members of the Public Health Service in teaching basic mosquito taxonomy during the past 25 years. The first 3 parts incorporate many of the ideas and illustrations in PHS manuals, pictorial keys, filmstrips and motion pictures in a new workbook format: trying to involve the student in a learning, recall and answering method of teaching. Part I deals with the basic differences between. anopheline and culicine larvae. Part II is concerned with the detailed morphology of mosquitoes used in identification. Part III deals with the generic characteristics of the 11 genera of North American mosquito larvae. Part IV is a quiz. Part V is an illustrated key to some 39 of the more impor- tant species of mosquitoes in North America, the ones that teachers often have available in quantity. This work book should be useful in teaching students both the method of using a key and the identifying characteristics of many Important species. It should also be helpful to technicians at many Mosquito Control Districts in identifying the common and important species. HOW TO USE THIS BOOKLET The purpose of this self-instructional Work Book is to teach, not to test. It has been specially written so that you can learn by doing. Parts I, /I, and III can be completed with a pencil, each student setting his own pace, taking whatever time is necessary. Read each page carefully.Write in the answers as you work through the Work Book and compare your answers with those in the Answer Book. REMEMBER --Read EVERYTHING carefully, more so than ytu ordinarily do. ..Work through each paragraph and page ONE STEP AT A TINE. -.Do your best to answer all the questions BEFORE you look back or use the answer book. When you have completed Parts I, II, and III, use a microscope and the illustrated key in Part V to identify specimen mosquitoes, which your instructor will provide. PART I What is an Anopheles or a Culicine Larva? There are four stages in the life history of mosquitoes: larva The first three states are aquatics the fourth, or adult state, is aerial. In most species the adult females, but not the males, are bloodsucking. TEST YOURSELF:Draw a line from each name to the appropriate drawing. 3. pupa 4.adult Mosquito larvae can be distinguished from all other aquatic insects by a combination of two characters: 1. They have no legs, and 2. The thorax is wider than the head or abdomen. i> HEAD r.r.2.- no leg >THORAX !ABDOMEN 4 These are not mosquito larvae but are found commonly in collections of standing water. These aquatic insects have legs on the thorax. DAMSUL FLY DRAGONFLY MAY FLY BEETLE These aquatic insects have the thorax about as wide as the head and abdomen. MIDGE LARVA RAT-TA iLRD MAGGOT TEST YOURSELF:Circle the numbero of the specimens illustrated below that are mosquito larvae. 1. 2. Mosquitoes are divided into two main types known as"anopheline" or "culicine." An anopheline mosquito larva has palmate hairs and no air tube; aculicine mosquito larva has no palmate hairs but does have an air tube. NO PALMATE HAIRS CULICINE ANOPHELINE The palmate hairs (after the palm of the hand or a palm frond) arepalm- shaped structures present on the abdomen of anopheline larvae and absent in culicine larvae. AIR TUBE ABSENT; ABDOMEN WITH PALMATE HAIRS palmate hair The air tube is a cylindrical structure arising from the eighth abdominal segment. It is present in the culicine larvae but absent in the anopheline larva. AIR TUBE PRESENT' ABDOMEN WITHOUT PALMATE HAIRS /1/ NO PALMATE HAIR The malaria mosquito belongs to the group, or genus (plural - genera), named Anopheles. The term "anopheline" is derived from this name. Si:udy the anopheline larva pictured here. MALARIA MOSQUITO LARVA Anopheles = " anopheline" mosquito larva Remember these three facts to identify an anopheline, or malaria-mosquito larva: 1. When resting, it lies parallnl to the water surface. 2, It has no air tube. 3. It has palmate hairs which help keep the abdomen at the water surface. TEST YODRSELV: Mark out the wrong statement in (a) and (b). The malaria mosquito larva can be recognized in the field with th3 naked eye, for it Hangs from the water surface. (a) Lies parallel with the water surface. f Has an air tube. (b) Does not have an air tube. Water Surface Fill in the blank in the statement below: In the laboratory, with the aid of a microscope, you can see palm-shaped structures, called on some of the abdominal segments. 11 The term "culicine" mosquito comes from the genus named Culex, a well -known genus of pest mosquito. Study this drawing of a culicine larva. ..NO PALMATE HAIRS AIR TUBE PRESENT CULICINE (PEST) MOSQUITO LARVA 12 These characteristics will enable you to identify the larva of a culicine, or pest mosquito. 1. It hangs at an angle to the water surface. 2. It has an air tube. 3.' It does not have palmate hairs, AIR TUBE _ "r4, 13 TEST YOURSELF:Culicine larvae can be identified by three characters: 1. 2. 3. 14 TEST YOURSELF:The two important types of mosquito larvae are called: 1. or 2. or Write the appropriate names over the larvae pictured. 15 PART II Morphology of Mosquito Larvae The mosquito larva is divided into three body regions: head, thorax, and abdomen. Structures on each of these body regions are used in identifying mosquito The head of an anopheline larva is very different than that of a culicine larva. It is longer than wide with six frontal pairs across the frontal area (the middle of the dorsal or upper surface) and four hairs on the anterior end, called the inner and outer clypeal hairs. INNER. CLYPEAL HAIR OUTER CLYPEAL HAIR FRONTAL HAIRS '\\\ \\M\11NYralitthillffillomoir Head of anopheline larva 17 The head of all North American culicine larvae (except Uranotaenia) is as wide as, or wider than, long. The important hairs across the middle of the dorsal surface of the head are called the upper head hair, lower head hair, and preantennal hair. Observe in the drawings the relative positions of the upper and the lower head hairs. In drawing A, the lower head hair appears to be in an uppermost position, but in drawing B, which shows the live larva hanging suspended from the water surface, the lower head hair is below the upper head hair. antennal hair Head of culicine Culicine larva in resting position The head hairs are all numbered. Some workers, and some identification keys, refer to the hairs by numbers rather than by names.The hairs are listed below by both number and name. Culex 01.1Anopheles 1. preclypeal 8-9, sutural (occipital) 2, inapt clypeal 8. sutural (inner) 3, outer clypeal 9. transsutural 4. postelypeal 3, inner frontal in anophelines; MOM Hairs 2 and 3 are absent upper head in culicines in culieines 6, taid frontal in anophalines; lover head in cuticines outer frontal in anopheles; preafttennal in culicines 19 TEST YOURSELF: number and label the hairs on the dorsal (or upper) surface of the head. Culex Aedes 20 The antenna consists of a tubular shaft bearingan antennal hair, a terminal antennal hair, and, at the tip, a dorsal and ventralsaber. The antennal hair may be single or branched. Its position on the shaft is important; it may be located at the middle, or at some other part.